Selectively power-operated drawer structure



Feb. 10, 1959 o. A. BECKER SELECTIVELY POWER-OPERATED DRAWER STRUCTUREFiled June 5, 1956 6 Sheets-Sheet 1 PM! -ir illJv l Feb. 10, 1959 o. A.BECKER 2,873,159

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SELECTIVELY POWER-OPERATED DRAWER STRUCTURE Filed Jun 5, 1956 6Sheets-Sheet 5 Feb. 10, 1959 o. A. BECKER 3,

SELECTIVELY POWER-OPERATED DRAWER STRUCTURE Filed June 5, 1956 6Sheets-Sheet 6 Fig /7 my {6 a6 1b! in: J

+ #vmswroE United States Patent SELECTIVELY POWER-OPERATED DRAWERSTRUCTURE Otto Alfred Becker, Saarbrucken, Saar Territory ApplicationJune 5, 1956, Serial No. 589,475 Claims priority, application GermanyJune 13, 1955 14 Claims. (Cl. 312-223) The drawers or the like in desks,file cabinets etc.

have previously been actuated only by hand. In many cases, however, hisdesired to relieve the personnel working at the desks or file cabinetsfrom the physical eifort involved inthe pulling out and pushing back ofthe drawers, which are sometimes of considerable weight.

It is an object of the invention to solve that problem in a simple andeconomical manner.

The invention provides a device for mechanically extending andretracting the drawers or the like arranged it: desks, file cabinets orthe like. The drawers or the like areextended only to such an extent asto remain in the guides with their rear end. The extending of thedesired drawer is caused by the actuation of a certain selector key,whereby the drawer may be coupled to an extending means. The actuationof a return key causes the extended drawer to be retracted to itsinitial position. The extending and retracting deviceis disposed insidethe desk, preferably in the longitudinal direction of the drawers.

The movement of the drawers or the like is either effected directly byan electric motor or by a combination of springs and an electric motor,the springs causing the drawers to be extended and the electric motorcausing the drawers to be retracted and the springs to be strained.

According to another embodiment of the invention the retracting movementmay also be effected by springs. In that case the springs effecting theretracting movement are of such a strength as to re-strain the extendingsprings to retract the drawer at the same time. The retracting springsare strained by an electric motor.

The resilient operation of the drawers by springs is particularlyfavorable if the drawers meet during their movement an obstacle orcontact the body of a person working at the drawer. Appropriate stoppingmeans may be employed to stop the drawers or the like in any desiredextended position.

Several illustrative embodiments of the invention are shown in theaccompanying drawings, in which- Fig. l is a perspective view of a deskprovided with the device according to the invention;

. Fig. 2 is a side view of the desk shown in Fig. 1, with a partlybroken-away side wall;

Fig. 3 is a sectional view showing on an enlargedscale the selector keyscausing the drawers to be extended;

Fig. 4 shows the combination of an end stop for the driver strip with anormally closed contact;

Fig. 5 is a sectional view showing on an enlarged scale the return keycausing the retracting of the drawers,

Fig. 6 is a sectional view showing on an enlarged scale 2,873,159Patented. F eb. 10, 1959 r 2 the stop key whereby the drawers can bestopped in any desired extended position;

Fig. 7 is a sectional view showing on an enlarged scale the release keycausing the stopped drawers to continue their extending movement;

Fig. 8 is a wiring diagram;

Fig. 9 is a side view of a desk, with partly broken away sidewall,provided with another embodiment of the device according to theinvention;

Fig. 10 is an enlarged view showing an end stop switch with broken awaycasing; I

Fig. 11 is an enlarged sectional view showing on an enlarged scale aspring-loaded cable drum effecting the extending of the drawers;

Fig. 12 is a sectional view showing on an enlarged scale the selectorkeys causing the extending of the drawers;

Fig. 13 is a sectional view showing on an enlarged scale the return keycausing the retracting of the drawers;

Fig. 14 is a wiring diagram,

Fig. 15 is a side view of a desk, with partly broken away side wall,provided with a further embodiment of the device according to theinvention, r

Fig. 16 shows the drive means for the spring-loaded cable drum, and tFig. 17 is a wiring diagram.

Fig. 1 is a perspective view showing a desk having a left-hand pedestal1, a right-hand pedestal 2 and a desk top 3 in connecting the twopedestals. The top face 4 of each of the pedestals l and 2 protrudesforwardly beyond the desk top and is provided with a row sot selectorkeys. Each of the selector keys 6 is associated with a drawer 7 arrangedin the pedestal 1 or 2. Operation of one of the selector keys 6 willcause thelextending of a certain drawer 7 frorr'rthe pedestal 1 or 2.Operation of thereturn key 8 will cause the extended drawer to beretracted to its initial position. .The stop key9 is operable to stopthe drawers 7 in any desired extended position. Operation of the releasekey 10 will cause the stop key 9 to return to its initial position topermit the drawer 7 r to continue its interrupted extending movement. a

Fig. 2 is a side view of the right-hand pedestal 2 with partly brokenaway side wall 11. Theopjerat 'ng means for the drawers 7 is disposedbetween the drawers and the side wall 11. The operating means comprisesa driver'strip 12 which is disposed at right angles to the direction ofmovement of the drawers 7 and which is guided at its (upper and lowerends in guides 13 and. 14 and connected a't each of such ends to thelower strand of an endless drive chain 15 or 16, which extends parallelto the direction of movement of the drawers.

The driver stripflZ carries a driving pin 17 for each drawer. Thisdriver pin serves to couple the respective drawer 7 with the driverstrip 12. Also for the purpose of coupling the drawers 7 to the driverstrip 12 a coupling lever 18 is provided at the rear end of the drawers7. Actuation of one of the selector keys 6 operates a cable 20 extendingaround guide pulleys 19 to lift a coupling bolt23 associated with theselector key an d arranged at the rear wall 22 of the pedestal. Thislifting of the coupling bolt 23 is effected against the force of atension spring 21. Thusthe coupling lever of the drawer 7 associatedwith the actuated selector key 6 is released. The tension spring 24causes the released coupling lever 18 to'perform a pivotal movement toengagethe driving pin 17 of the driver strip; 12. Thus the drawer iscoupled to the driver strip. s

Figl. 3 is an enlarged view of the selector key 6. The

a compression spring 25 is held in its depressed position by a latch 28which falls in automatically under the action of a tension spring 27.The depression ofthe selector key '6 causes a pivotal movementcf amanned lever selector key 6 depressed into the bearing body 26 against29 carried in the bearing body 26. Thus the coupling bolt 23 connectedby the cable 20 to the arm 29a of the lever 29 is lifted to establishthe coupling between the drawer 7 associated with the selector key 6 andthe driver strip 12, as has been described hereinbefore. At the sametime the arm 29a of the lever 29 closes a normally open contact 30 afterthe coupling bolt 23 has been lifted to establish the coupling betweenthe drawer and the driver strip 12.

The endless chains 15 and 16 extending around sprockets 31, 32 and 33,34, respectively, are coupled to each other by an endless chain 35,which extends around the sprockets 32 and 34 of the chains 15 and 16. Tothis end the sprockets 32 and 34 are formed as double sprockets. Thedouble sprocket 32 for the chains 15 and 35 is carried on a shaft 36,which is coupled by means of an endless belt 37 to the shaft of anelectric motor 38. The closing of the normally open contact 30 uponactuation of the selector key 6 closes the circuit of the electric motor38 (Fig. 8), which drives the endless chains 15 and 16 and thus movesthe driver strip 12 coupled thereto to the front side of the drawer. Themovement of the driver strip causes the drawer coupled thereto to beextended out of the desk pedastal.

Shortly before the drawer being extended has reached its front endposition the driver strip 12 engages an end stop buffer 40 loaded by acompression spring 39 (Fig. 4). By this engagement the end stop bufferis longitudinally displaced and held in that position by a latch 42,which falls in automatically under the action of a tension spring 41.The longitudinal displacement of the end stop bufler 40 opens a contact43 to interrupt the circuit for the drive motor 38.

The retracting of the extended drawer to its initial position is causedby an actuation of the return key 8 (Fig. This will cause the shiftingof a change-over switch 44, whereby a new circuit for the drive motor 38is closed. As contrasted with the circuit last interrupted the circuitnow closed carries current in the opposite direction so that the senseof rotation of the drive motor is reversed. The return key 8 is formedlike the selector key 6 and like the latter is held in its depressedposition by an automatically falling-in latch 45. Shortly before thedrawer has reached its rear end position the driver strip 12 whicheffects the retracting of the drawer engages the arm 46a of the bellcrank 46 pivotally movable on the pivot 47. The other arm 46b of thebell crank is connected by a branched cable 49 extending around guidepulleys 48 to the latches 28 for the selector keys 6, the latch 45 forthe return key 8 andthe latch 42 for the end stop buffer 40. Theresultmg plvotal movement of the bell-crank 46 causes all latches 28, 42and 45 to move into the release position so as to release the depressedselector keys 6 and 8 held in the depressed position by the latches, aswell as the end stop butter 40 which has been moved out of its initialposition and held in said displaced position by the latch 42. As the endstop butter 40 returns to its initial position the normally closedcontact 43 closes to eliminate the break in the circuit at that point.

Actuation of the stop key 9 (Fig. 6) will cause the extending movementof the drawers to be arrested in any desired position. The stop key 9 isformed like the keys 6 and 8 and like-the same is held in itsdepressedposition by an-automatically falling-in latch 50. Actuation of the stopkey operates a double-armed lever 51 to open a contact 52, whereby thecircuit is interrupted and the drive motor is stopped. The release key(Fig. 7) is actuated if it is desired to continue the extending movementof the drawer from the position in which it was stopped. This releasekey is depressed into the bearing body 54 against the pressure of acompression spring 53 to swing a lever 56, which is loaded by a tensionspring 55 and is carried on the same shaft 57 a the laugh/50 for thestop key 9. Thus the latch 50 is swung into its release position torelease the stop key. At the same time the drawer extending circuit,which was opened upon actuation of the stop key, is closed. Uponactuation of the release key 10 the drawers will continue on to theextended position from any intermediate position in which they werestopped by the stop key 9. The cable 49 is branched to connect the latch50 of the stop key 9 also to the bell-crank 46. As soon as the drawer 7has reached its initial position the latch 50 is swung into its releaseposition as well as the latches 28, 42 and 45 by-the pivotal movement ofthe bell-crank 49 upon actuation of the release key 10. Thus the stopkey 9 is released to permit the contact 52 to close and eliminate thebreak in the circuit at that point.

In the illustrative embodiment of the invention shown in Figs. 9 to 14the drawers 7 are extended by spring force. To this end each drawer 7has associated therewith a spring-loaded cable drum which is disposed atthe rear wall 22 of the pedestal and accommodates a spiral spring 59.The end of the cable 60 wound from the spring-loaded ca'ble drum 58extends parallel to the direction of movement of the drawer and around aguide pulley 61 disposed next to the front wall of the pedestal and isconnected to the rear end of the appertaining drawer 7. The rear wall ofthe pedestal 22 carries for each drawer a latch 63, which is loaded by atension spring 62 and when the drawers are in their initial positionengages a rigid counterlatch 64 disposed at the rear end of the drawers.Thus the drawer 7 subjected to the tension of the cable 60 is held inits initial position. Each of the latches 63 is connected by a cable 66,which extends around guide pulleys 65, to the arm 67a of a double-armedlever 67 .(Fig. 12), which is connected to a selector key 68. De-

pression of the selector key 68 against the pressure of a spring 69 willpivotally move the lever 67 whereby the latch 63 is disengaged from thecounterlatch 64 carried by the drawer 7 and the drawer 7 addressed bythe selector key 68 is released. Then the drawer 7.is extended by thecable 60, which winds up on the spring-loaded cable drum 58. Thisextending movement is continued until the drawer 7 engages a stop in itsfront end posi tion. A return key 70 is actuated to retract the extendeddrawer 7 to its retracted position. The return key 70 may be depressedagainst a compression spring 71 into the bearing body 72 and is held inthe depressed position by an automatically falling-in latch 73. As thereturn key 70 is depressed a two-armed lever 75, which is rotatablymounted in the bearing body 72 and loaded by a tension spring 74, ispivotally moved so that its arm 75a closes a normally open contact 76and with it the circuit for the drive motor 38.

The same operating means as in the embodiment described last is providedfor returning the drawer 7 into its retracted position. In this case thedriver strip 77 carries no driving pins 17 and is disposed in theinitial position next to the front wall of the pedestal. When thecircuit for the drive motor 38 is closed by actuation of the returningkey 70 the endless chains 15 and 16 are driven and the driver strip 77coupled thereto is moved rearwardly to move the drawer back to itsinitial position since the driver strip 77 engages an angle stop 78 atthe rear end of the drawer 7 when the same is extended. As the drawerreturns to its initial position the driver strip 77 engages achange-over switch 79, whereby the direction of current flow in thedrive motor is reversed. Thus the sense of rotation of the drive motor38 is reversed so that the driver strip 77 is returned to its initialposition. Shortly before the driver strip 77 has returned to its initialposition the change-over switch 79 is shiftcd. This is effected by acontrol slide 81, which is actuated by the driver strip and coupled by arod 80. This slide 81 is longitudinally moved by the driver strip toshift the change-over switch. As the driver strip 77 approaches itsinitial position it engages the arm 82a of a bell-crank $2 to mo e thelat e T e arm Q1 0! the :5 bellcrank 82 is conuecte'dby a cable 83 tothe latch 73 for the return key 70 so thata pivotal movement of thebell-crank 82 will swing the latch 73 to its release position. When thereturn key has been released by the latch 73 the lever loaded by thetension spring 74 can return to its initial position; Thus the normallyopen contact 76 held closed by said lever is permitted to open andinterrupt the circuit for the drive motor 38. Fig; 14 shows the wiringdiagram for the illustrative embodiment just described. a a

Another embodiment of the invention is shownin Figs. to 17. In thatembodiment the drawer addressed by a selector key is extended from thepedestal under the action of the spring-loaded cable drum 58, just as inthe foregoing embodiment. In the present embodiment the retracting ofthe extended drawer 7 iseifected by the spring force of a spiral springSS. The spiral spring 85 is strongenough to strain the spiral spring 59in the spring-loaded cable drum during the retracting of the extendeddrawer. The spiral spring 85 is strained by an electric motor 86.

As in the foregoing embodiment the driver strip 87 is disposed next tothe front wall of the pedestal in its initial position. The driving ofthe extended drawer during the retracting movement is also efiected byan angle stop 78 carried at the rear end of the drawer. During theretracting of the drawer to its initial position the driver strip 87 ismoved rearwardly by the action of the spiral spring 85. After the drawerhas reached its initial position the driver strip 87 is returned to itsinitial position by the electric motor 86, which strains the spiralspring 85 at the same time.

To this end a cable 92 is provided, which has its ends wound on cabledrums 88 and 89 rotatably carried at the rear wall of the pedestal andextends around guide pulleys 90 and 91 rotatably carried by the frontwall of the pedestal. The spring-loaded cable drum 88 accommodates thespiral spring 85 for retracting the drawers. The cable drum 89 rotatablycarried on a shaft 98 is connected to a ratchet wheel 93, which isengaged by a pawl 94 whereby the rotation of the cable drum 89 in onedirection is prevented so that the spring-loaded cable drum 88 is unableto unwind the end of the cable 92 wound on the cable drum 89.

Upon disengagement of the pawl 94 from the ratchet wheel 93 the cable 92is wound by the spring-loaded cable drum 88, whose spring is strained,from the cable drum 89 onto the cable drum 88. At the same time thedriver strip 87 connected to the cable 92 retracts the drawer from itsextended to its initial position.

The disengagement of the pawl 94 is caused by the actuation of a returnkey connected to the pawl 94 by the cable 96. That return key may beformed like the selector key shown in Fig. 12. As soon as the driverstrip 87 has pushed the extended drawer back to its initial position itactuates a contact actuating slide 95, whereby a contact 97 is closed.

The cable drum 98 is carried on a shaft 98 which is connected by anendless chain 107 to a shaft 104, which can be coupled by a clutch 99with the electric motor 86 provided to strain the spiral spring 85. Theclutch 99 is engaged and disengaged by a clutch lever 100.

Closing of the contact 97 causes an electromagnet 181 to be energized.When energized the electromagnet attracts an armature 102 connected tothe clutch lever 100. The resulting pivotal movement of the clutch lever100 causes the clutch 99 to engage and establish the connection betweenthe shaft 104 and the electric motor 86. At the same time the clutchlever 100 actuates a contact 103 to close the circuit for the electricmotor 86.

When the electric motor hasthus been started the cable drum 89 is drivento wind the cable 92 from the spring-loaded drum 88 onto the cable drum89. Thus the spiral spring 85 is strained and the driver strip 87returned to its initial position.

As soon as the driver strip 87 has returned to its initial position itwill actuate a slide 105, which 'is connected by a rod 106 to thecontact actuatingslide 95. Actua' tion of the slide 105 will return thecontact actuating slide to its initial position whereby the contact 97,which was held closed by the contact actuating slide, is allowed toreturn to its normal open position and thus to interrupt the circuit forthe electric motor 86 and the electromagnet 101.

Thus the electric motor 86 is stopped and the armature 102 is releasedby the electromagnet 101.. As the armature 102 is released by theelectromagnet the electric motor is uncoupled from the cable drum.

The invention is not only applicable to drawers, but mayalso be used forthe actuation of lowering devices for typewriters and other machineswhich are to be moved to ap'os'itionfor use by a pivotal movement,particularly by an upwardly directed pivotal movement. In this base theoperating means are disposed at a suitable position of the swingingdevice in such a manner that the pivotal extending and retractingmovements are produced by the forward and backward movements of thedescribed operating means.

The invention is not restricted in its application to drawers in desks,but may also be applied to operate drawers, containers or articlesdisposed in a frame, shelf, cabinet, counter or trough, for otfice orother use. The invention is not restricted to the embodiments describedbut includes in its scope also considerable modifications thereof withinthe spirit of the invention.

I claim:

1. Equipment for extending and retracting a plurality of verticallystacked slidable elements in a piece of furniture; said equipmentcomprising a prime mover and transmitting means; said transmitting meansincluding flexible drive means, a driving member, and a plurality ofdriven members; a portion of said flexible drive means being disposedlongitudinally with. respect to the length of said slidable elementsalongside the said elements; the said driving member being drivable bysaid drive means and being disposed transversely with respect to thelength of the said slidable elements alongside the said elements;

said driven members being mounted respectively on each of the saidelements and being operatively positioned to engage said driving member;said driving member extending across the driven members of all theelements of the said vertical stack.

2. Equipment as set forth in claim 1, in which said prime movercomprises an electric motor and said transmitting means are arranged toreceive power from said motor in an extending direction and to transmitsaid power directly to said elements, and which comprises stopping meansarranged to stop said motor responsive to the arrival of any of saidelements at a predetermined end position of its extending movement.

3. Equipment as set forth in claim 1, which comprises means forarresting said transmitting means responsive to the arrival of apreviously extended element at a predetermined end position of itsretracting movement.

4. Equipment as set forth in claim 1, which comprises a stop keyoperable to interrupt the extending movement of said element in anydesired position and a release key operable after the operation of thestop key to cause said interrupted extending movement to be continued.

5. Equipment as set forth in claim 1, in which said transmitting meanscomprise a spring motor.

6. Equipment as set forth in claim 1, in which said transmitting meanscomprise a plurality of springs each of which is adapted to extend oneof said elements, and joint means for retracting said elements.

7. Equipment as set forth in claim 1, in which said transmitting meanscomprise a first spring motor for extending said elements, and a secondspring motor stronger than said first spring motor and strainable bysaid prime nectible to any of said elements for moving the same at leastin said retracting direction.

9. Equipment as set forth in claim 2, in which said stopping means iscommon to all said elements.

10. Equipment as set forth in claim 3, in which said driving member ismovable from an initial position to retract said elements and whichcomprises means operable by said prime mover to return said driver toits initial position responsive to said arrival of a previously extendedelement at said predetermined end position of its retracting movement,and stopping means arranged to arrest said prime mover responsive to thearrival of said driver in said initial position.

11. Equipment as set forth in claim 5, in which said transmitting meanscomprise at least one spring motor for transmitting power to saidelements at least in one of said directions and said prime movercomprises an electric motor for straining said spring motor.

12. Equipment as set forth in claim 11 in which said spring motor isoperable to transmit power to said elements in both said directions.

13.-Equipment as set forth in claim 6, in which said joint meanscomprise a spring motor.

14. Equipment as set forth in claim 6, in which said joint means arearranged to receive power directly from said prime mover.

References Cited in the file of this patent UNITED STATES PATENTS2,187,012 Brenner Jan. 16, 1940 2,621,995 Zenner et al. Dec. 16, 1952

